Examine source code of user-select

{
  "manifest_version": 2,
  "name": "user-select",
  "version": "1.2",
  "description": "A add-ons the web which can not select text and copy.",
  "homepage_url": "https://github.com/fortystory/user-select",
  "icons": {
    "48": "icons/icon.ico"
  },
  "browser_action": {
    "default_icon": "icons/icon.ico",
    "default_title": "user select"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "user_select.js"
      ]
    }
  ]
}